The final stretch for the jodi arias trial. Dozens of witnesses, hundreds of questions. The last testimony today closing arguments start tomorrow and abc's ryan owens is back with all the latest. Reporter: Could today finally be it? After four months, 36 witnesses, is this the last day of testimony in the jodi arias murder trial? That's what the judge promised the jury last week, warning today might be a marathon. We are going to stay here until we finish. Reporter: On tap today, yet another set of dueling psychologists with very different opinions about what drove the 32-year-old killer to shoot and repeatedly stab her ex-boyfriend. The simple answer is he attacked me. Reporter: Arias has changed her story many times about that day in june of 2008 when she killed mormon businessman travis alexander. First she said she wasn't there. Then she concocted an elaborate tale of masked intruders who butchered her former boyfriend but spared her. Finally, she fessed up but claims she can't remember the killing but knows it was self defense. Were you crying when you were shooting him? I don't remember. Reporter: The defense case lasted 38 days, an unbelievable 18 with jodi arias herself on the stand. Nothing but the truth so help you god. Reporter: But after this prosecution psychologist labeled her a ma nip tiff liar with a violent streak arias' attorneys convinced the judge to let them re-open their case. Their final witness, san diego psychologist dr. Robert geffner. He never examined arias but he is expected to say what her other experts did. She's a battered woman, not a cold-blooded killer. Jurors after a while if they start to feel preached to. If they start to feel like we've already heard an expert talk about this, they begin to get resentful. Reporter: It also means the prosecutor will get to call yet another of his own psychologists to the stand. For "good morning america," ryan owens, abc news, phoenix. Okay, let's get more from "gma" legal analyst dan abrams. Ay, one more longy. Yeah. Today and then the marathon trial heads into the closing arguments. When you strip all of this away, what does the defense have to do tomorrow? They have to somehow avoid premeditation, right. This is not a case about whether jodi arias is going to get convicted. She's going to get convicted or there will be a hung jury but she's not going to get acquitted so the question becomes, what is she going to get convicted of? And if I'm the defense, that's my focus. The focus is not on the self-defense. Yes, you have to make that part of your closing argument, yes, you have to argue that to the jury. But I think going through your mind, the most important thing you want to try to convince the jurors is, there's not proof beyond a reasonable doubt of premeditation here. That could increase the significance of the decision by the judge. Has not been made yet whether or not to allow manslaughter. This is a really important question. The question is as a legal matter should the judge offer manslaughter as an option to the jurors? The prosecutors say there's no evidence of manslaughter. The defense says it should go to the jury with that question. I don't think there's a real good chance she'll get ccted of manslaughter even if the judge gives it, the problem for prosecutors is if manslaughter is offered as an option, it could lead to a compromise verdict and the compromise would be second degree murder. Second degree murder would be a big victory for jodi arias in connection with this case. Considering how much evidence there is against jodi arias, if these jurors were to, quote, compromise and convict of second degree murder, yoed jodi and her attorneys in my view walk away winners. Of course, there will be no death penalty. That's correct. Thanks very much.

This transcript has been automatically generated and may not be 100% accurate.

{"id":19081559,"title":"Final Day of Testimony In Arias Trial","duration":"3:53","description":"A judge promised jurors that there would be no more witnesses in the 4-month long murder trial.","url":"/GMA/video/jodi-arias-trial-update-final-day-testimony-closing-19081559","section":"GMA","mediaType":"Default"}